1. Field of the Invention
The present invention relates to a cable tightening device and, more particularly, to a cable tightening device for tightening or loosening a cable so as to bind or release a cargo.
2. Description of the Related Art
A cable tightening device is mounted on a wheeled vehicle having a larger size, such as a truck or the like, to tighten a cable which is wound around a cargo so as to tighten the cargo.
A conventional cable tightening device in accordance with the prior art shown in FIG. 8 comprises a fixed unit 60 including a base 61, a rotation member 80 rotatably mounted on the base 61 of the fixed unit 60 to wind and unwind a cable (not shown) by rotation of the rotation member 80, and a movable unit 70 including a movable member 71 rotatably mounted on the rotation member 80 and movable relative to the base 61 of the fixed unit 60 to drive the rotation member 80 to rotate relative to the fixed unit 60 in a one-way direction. The fixed unit 60 further includes two opposite ratchet wheels 62 secured on two opposite ends of the rotation member 80 to rotate the rotation member 80, and a stop plate 65 movably mounted on the base 61 and releasably engaged with the ratchet wheels 62 to allow the ratchet wheels 62 to rotate in a oneway direction. The base 61 of the fixed unit 60 has a distal end provided with a bolt 63 and a nut 64. The movable unit 70 further includes a push plate 72 movably mounted on the movable member 71 and releasably engaged with the ratchet wheels 62 of the fixed unit 60 to push the ratchet wheels 62 of the fixed unit 60 to rotate in a oneway direction, and a release member 73 mounted on a side of the push plate 72 to pull the push plate 72 to move relative to the ratchet wheels 62 of the fixed unit 60 so as to lock the movable member 71 of the movable unit 70 onto the base 61 of the fixed unit 60 or to unlock the movable member 71 of the movable unit 70 from the base 61 of the fixed unit 60. Thus, the release member 73 of the movable unit 70 is pulled outwardly to pull the push plate 72 to detach from the ratchet wheels 62 of the fixed unit 60 and to unlock the movable member 71 of the movable unit 70 from the base 61 of the fixed unit 60 so that the push plate 72 of the movable unit 70 skips the ratchet wheels 62 of the fixed unit 60 when the movable member 71 of the movable unit 70 is rotatable on the rotation member 80 to move toward the base 61 of the fixed unit 60.
In operation, when the movable member 71 of the movable unit 70 is pivoted toward the base 61 of the fixed unit 60, the push plate 72 of the movable unit 70 is moved with the movable member 71 to push and rotate the ratchet wheels 62 which rotates the rotation member 80 relative to the base 61 of the fixed unit 60. On the contrary, when the movable member 71 of the movable unit 70 is pivoted outwardly relative to the base 61 of the fixed unit 60, the push plate 72 of the movable unit 70 passes by the ratchet wheels 62 so that the rotation member 80 is not rotated by the push plate 72 of the movable unit 70. Thus, when the movable member 71 of the movable unit 70 is pivoted relative to the base 61 of the fixed unit 60 in a reciprocal manner, the push plate 72 of the movable unit 70 is moved with the movable member 71 to push the ratchet wheels 62 to rotate in a oneway direction so that the rotation member 80 is rotated successively in a oneway direction to wind the cable successively so as to tighten a cargo.
In assembly, an extension strap (not shown) has a first end mounted on the bolt 63 of the base 61, and a snapping hook (not shown) is mounted on a second end of the extension strap and is hooked on a wheeled vehicle, such as a truck and the like, so that the base 61 of the fixed unit 60 is attached to and supported by the wheeled vehicle via the extension strap and the snapping hook before the cable is tightened.
However, it is necessary to provide the bolt 63 and the nut 64 for mounting the extension strap and the snapping hook, thereby increasing the costs of fabrication. In addition, it is necessary to mount the bolt 63 and the nut 64 on the base 61 of the fixed unit 60, thereby greatly causing inconvenience in assembly of the cable tightening device. Further, the nut 64 is easily unscrewed from the bolt 63 during a long-term utilization, thereby causing inconvenience in operation of the cable tightening device.